1. Field of the Invention
The present invention relates to the treatment of waste and wastewater. More particularly, the present invention relates to a method and apparatus for using ozone in a pressure vessel to treat polluted waste and wastewater.
2. Description of the Relevant Art
The introduction of organic and inorganic substances into water supplies results in the pollution of the water are a part of the modern world. Pathogens may also be introduced into the water supply. Many of these additions to the water supply are the result of human activity, including agricultural development and industrial production, as well as the output of human communities. In some cities, approximately 200 gallons of wastewater per person are produced. This wastewater, including waste from household, agricultural, and industrial sources, is generally referred to as domestic sewage. At a certain point these additives stress the water supply to dangerous levels and require treatment and eradication.
Several methods have been developed to treat wastewater to prepare it for its return to the general water supply. Early attempts at wastewater treatment were directed to mechanical methods of sedimentation and enhancing exposure to oxygen and sunlight. The methods used today for wastewater treatment include primary treatment (passing the wastewater through screens to remove coarse elements and allowing the water to stand in tanks so that the remaining solid matter settles out) and secondary treatment (directed to the oxidization of organic matter and the removal of inorganic material and the neutralization of any bacteria and viruses that might be present in the wastewater). Secondary treatment includes the substeps of initial treatment (oxidation in oxidation ponds or filtration through crushed stone or gravel [or filters or disks] and the use of microorganisms to break down the organic and inorganic matter) and the processing of the remaining solids and liquids through the use of a settling tank and a unit for anaerobic digestion. (The outflow is directed into the settling tank to allow for settlement. Once separated, the liquid portion receives further treatment before being released into the environment, while the organic matter of the sludge is treated for stabilization using an digester.)
While being generally suitable for most forms of wastewater, these procedures fail to satisfactorily treat wastewater that is both chemically and biologically hazardous. Industrially produced chemicals such as chlorinated hydrocarbons (either aliphatic or aromatic) commonly enter wastewater. Other chemicals frequently produced at the industrial level include trichloroethylene, cyanide (from metal plating), sugars (from confectionery production), various fats, oils, and grease (from restaurants, auto facilities, and refineries), products from the plating industries, such as copper, cadmium, zinc, manganese, lead, ferrous iron, silver, and surfactants from soaps and detergents. Most of these chemicals are not biodegradable and are difficult to render nontoxic. In addition, bacterial and viral pathogens are frequently found in wastewater. Filtration and chemical treatment have only limited effect on these pollutants.
As an alternative to mechanical methods of treating such industrial wastewater, ultraviolet light has been applied to assist in the breakdown of organic waste through oxidation. Ozone (O.sub.3) absorbs such light and releases oxygen atoms. These atoms react with water and result in the formation of OH radicals which are excellent oxidants. Ultraviolet light and ozone in combination with the reaction of OH radicals effects both chemical and pathogenic neutralization.
Several patents are directed to the treatment of wastewater using ultraviolet light in conjunction with an oxidizing agent. Examples of these patents include: U.S. Pat. No. 5,308,480, issued May 3, 1994, to Hinson et al. for APPARATUS FOR REMOVAL OF SOLID, CHEMICAL AND BACTERIAL WASTE FROM WATER; U.S. Pat. No. 5,302,298, issued Apr. 12, 1994, to Leitzke for PROCESS AND INSTALLATION FOR TREATING LIQUIDS CHARGED WITH POLLUTANTS; U.S. Pat. No. 5,234,606, issued Aug. 10, 1993, to Kazama et al. for METHOD AND SYSTEM FOR RECOVERING WASTEWATER; and U.S. Pat. No. 5,178,755, issued Jan. 12, 1993, to LaCrosse for UV-ENHANCED OZONE WASTEWATER TREATMENT SYSTEM.
While representing improvements in the treatment of wastewater, known systems for the treatment of chemically and pathologically polluted water fail to provide a system to efficiently, quickly, and inexpensively remove such pollutants. Accordingly, such a system is wanting in the treatment of waste and wastewater.